Save the original base image ref for snapshots.

Save the base image ref in instance system metadata for tracking
purposes.

(This is modified code originally from Rick Harris.)

Change-Id: I574c597c7ff2e55675ebdaa7b3213b53e61a94b7

2 files changed, 24 insertions, 3 deletions

diff --git a/nova/compute/api.py b/nova/compute/api.py
index dcc6a7f06..9f99e00dc 100644
--- a/nova/compute/api.py
+++ b/nova/compute/api.py
@@ -688,6 +688,16 @@ class API(base.Base):
             new_value = str(value)[:255]
             instance['system_metadata']['image_%s' % key] = new_value
 
+        # Keep a record of the original base image that this
+        # image's instance is derived from:
+        base_image_ref = image['properties'].get('base_image_ref')
+        if not base_image_ref:
+            # base image ref property not previously set through a snapshot.
+            # default to using the image ref as the base:
+            base_image_ref = base_options['image_ref']
+
+        instance['system_metadata']['image_base_image_ref'] = base_image_ref
+
         # Use 'default' security_group if none specified.
         if security_groups is None:
             security_groups = ['default']
@@ -1173,6 +1183,13 @@ class API(base.Base):
             'image_type': image_type,
         }
 
+        # Persist base image ref as a Glance image property
+        system_meta = self.db.instance_system_metadata_get(
+                context, instance_uuid)
+        base_image_ref = system_meta.get('image_base_image_ref')
+        if base_image_ref:
+            properties['base_image_ref'] = base_image_ref
+
         sent_meta = {'name': name, 'is_public': False}
 
         if image_type == 'backup':
diff --git a/nova/tests/compute/test_compute.py b/nova/tests/compute/test_compute.py
index 822c23e03..403d56f58 100644
--- a/nova/tests/compute/test_compute.py
+++ b/nova/tests/compute/test_compute.py
@@ -2508,10 +2508,14 @@ class ComputeAPITestCase(BaseTestCase):
         try:
             sys_metadata = db.instance_system_metadata_get(self.context,
                     ref[0]['uuid'])
-            self.assertEqual(sys_metadata,
-                    {'image_kernel_id': 'fake_kernel_id',
+
+            image_props = {'image_kernel_id': 'fake_kernel_id',
                      'image_ramdisk_id': 'fake_ramdisk_id',
-                     'image_something_else': 'meow', })
+                     'image_something_else': 'meow', }
+            for key, value in image_props.iteritems():
+                self.assertTrue(key in sys_metadata)
+                self.assertEqual(value, sys_metadata[key])
+
         finally:
             db.instance_destroy(self.context, ref[0]['uuid'])